function findMaxDeep(node) {
    let max = 0;
    function dfs(node, dep) {
        if (node.left && node.right) {
            max = Math.max(max, dep)
        }
        if (node.left) dfs(node.left, dep + 1)
        if (node.right) dfs(node.right, dep + 1)
    }
    dfs(node, max)
    return max
}